I've had some basic classical (piano and organ) music training, and I even had to do an exam, where we were given an A, and we had to write down a simple melody which was played on a piano. I don't find it hard as long as the music I have to listen to is clear and not polyphonic. However, as soon as there are more than 2-3 voices at the same time, i find it hard to differentiate.
I also find it difficult to even recognize heavily distorted chords on an electric guitar for example; even though a friend of mine who plays guitar says amplified electric guitar should be even easier to hear. I can't relate to the more 'heavy' music, because it often sounds like static, I can't hear it as tones. Is this a hearing problem, is it lack of training/experience or should I consult a doctor?